var Readable = require('stream').Readable;

var rs = new Readable;
let line = 97;
rs._read = ()=>{
    rs.push(String.fromCharCode(line++));
    if(line > 'z'.charCodeAt(0)) rs.push(null)
}

rs.pipe(process.stdout);
process.stdin.on('readbale', function(){
  let buf = process.stdin.read('abc')
  console.dir(buf);
//   buf.pipe(process.stdout)
})
rs.push('abc')
rs.pipe(process.stdout);
// buf.pipe(process.stdout)

// console.log(rs);
